Electrical condenser



Jam. 14, 1930. J. c. SNELL 3 ELECTRICAL CONDENSER Filed Dec. 1'7, 1924,

Patented Jan. 14, 1930 UNITED STATES PATENT" OFFICE JAMES C. SNELL, OF OAK PARK, ILLINOIS; ASSIGNOR 'IO PREMIER ELECTRIC COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS ELECTRICAL CONDENSER Application filed December 17, 1924. Serial No. 756,391.

The invention relates to electrical condensers and more particularly to those condensers which are used in radio service and systems.

One object of the invention is to provide a condenser with new and improved means for securing the rotor and stator plates in spaced relation relatively to each other.

Another object of the invention is to provide a condenser with new and improved [0 means for insulating the rotor plates from.

the stator plates so that only a substantially low loss of capacity will result.

A further object of the invention is to provide a condenser with means for taking up the wear on the rotor bearings so that there will-be substantially no longitudinal displacement of the rotor plates with respect to the stator plates.

A still further object of the invention is to provide an electrical condenser which is eflicient, simple in construction, and which may be produced at a low cost.

The invention consists in the several novel features hereinafter set forth and more particularly defined by claims at the conclusion" hereof.

In the drawings: Fig. 1 is a plan view of a condenser which embodies the invention, the panel or support to which it is secured being shown in section. Fig. 2 is. a vertical section on line 2-2 of Fig. 1. Fig. 3 is an enlarged section on line 3-3 of Fig. 2. Fig. 4 is a detail perspective of a portion of one of the supporting barsand one of the stator plates,

showing the improved means whereby they may be secured together. Fig. 5 is a detail perspective of a portion of the rotatable shaft and one of the rotor plates, showing the im proved means whereby they may be secured together. Fig. 6 is a perspective of one of the spring members for taking up the wear on the rotor-shaft bearings.

The invention consists in a condenser of new and improved construction which comprises a series of stationary substantially crescent-shaped plates 8 and a series of rotatableplates 9 interleaved with the sta-.

. tionary plates and also substantially crescent in shape. u The stationary plates 8 are spaced relatively to each other and are secured to supporting bars 10. These bars are formed of sheet metal and each is provided with a centrally and longitudinally disposed depressed portion 11 which is punched therein and which forms a pocket 12 in the bars respectively. The depressed portion 11 of each bar is provided with a plurality of transverse slots 14 which are sawed therein and through which lugs 8 integrally formed on the stationary plates 8 are adapted to extend respectively. After the lugs have been inserted into the slots 14, solder 15 is poured into the pockets 12 so that the stationary plates will be rigidly and securely held and secured together in spaced relation in a new and improved way.

I The inner ends of bars 10 are secured to the outer ends of cylindrical sleeves 16 by means of screws 17 which extend through holes 18 in the supporting bars 10 respectively (Fig. 2), and are secured to internal threads 16 formed in the sleeves 16. -The outer ends of bars 10 are secured to the outer ends of cylindrical sleeves 18 by means of screws 19 which extend through holes 20 in the supporting bars 10 respectively (Fig. 2) and are secured to internal threads 18 formed in sleeves 18 respectively. These sleeves are made of insulating material such as bakelite or the like. The inner ends of the sleeves 16 are internally threaded and are secured respectively to arms 21 on a spider 21. The inner ends of sleeves 18 are also internally threaded and are secured respectively to arms 22 on a spider 22. The spiders 21 and 22 together with the insulated sleeves 16 and 18 and supporting bars 10 form a frame for the stationary plates which is efiicient and which may be produced at a relatively low cost. A terminal conductor strip 35 is clamped to one end of one of the supporting bars 10 (Fig. 2), and has its inner end bent intothe pocket 12 and soldered thereto. Th's terminal is electrically connected to the stationary plates 8 through the supporting bars.

A supporting member 23 extends through an annular opening 24 in spider 21 and is riveted thereto as at 23 (Fig. 2). This member is adapted to be secured to a panel or (a meaevc new and improved connectionv to a sleeve or hollow shaft 28 which is disposed between the two spiders 21 and 22. This connection comprises lugs 9" which are integrally formed on the plates 9 and which extend through slots 28* which are transversely a sawed in a sleeve 0r hollow shaft 28. The

portion of the sleeve adjacent slots 28 is cut.

away as at 28 so that solder may be poured into the interior of the sleeve around the a portion of the lug-s9 which project therein to rigidly secure the plates 9. This cut-away portion serves to increase the distance between the shaft 28 and the inner edges of the stator plates when the rotor plates are not therebetween so that the mutual capacity between the shaft and the stator plates will be a minimum.

The outer end of shaft 28 is rotatably connected to the spider 22 by means of a screw 29, the head of which is provided with a conoidal surface 29' which is adapted to engage abearing surface 22 on the spider 22. The shank of screw 29 extends through an opening 22 in the hub of spider 22 and is adapted to engage internal threads 28 on .the shaft 28. A set screw 30 is adapted to adjustably hold screw 29 in place. The inner end of shaft 28 is screw-threaded to a shaft 31 and rigidly held thereto by means of set screw 32. Shaft 31 extends through hollow screw 26 and is provided with a shoulder 31 which has a conoidal surface which engages an internal conoidal bearing surface 23 on member 23. A sheet metal strip 36'is secured on an arm of the spider 21 adjacent the inner end of one of the sleeves 16. .The inner end of this strip is bent inwardly and is mounted on shaft 31, adjacent the end of shaft 28. A similar strip is secured on an arm of the spider '22 adjacent the inner end of one of the sleeves 18. The inner end of this strip is bent downwardly and is mounted on screw 29 adjacent the outer end of shaft 28. These strips 36 and 37 are provided with a curved portion .36 and 37 a respectively. These curved portions are adapted to engage the arms of the spiders 21 and 22 respectively in such a manner as to resiliently hold the ends of the strip adjacent the ends of the shaft '28 respectively. y means ofthese strips the spider 22 and the member 23 are thrust outwardly against the conoidal bearing surfaces on the shaft 31 and screw 29 respectively so that any wear on the bearings will be taken up. The outer ends of these strips are adapted to be used as terminals, the strips being electrically connected to the stator plates 9 through shaft 28.

YA handle or finger piece 33 is secured to the front end of shaft 32 which extends through and to the front of the support 25. A dial plate.34= is secured to the inner face of the finger piece 33 and is provided with suitable indications (not shown) to indicate with a stationary indicator (not shown) the different positions of the rotatable series of plates and the corresponding capacity values.

The invention is not to be understood as restricted tothe details set forth, since these may be modified within the scope of the appended claims, without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters'Patent, is:

1. In an electrical condenser, the com bination of a pair of members, one of which is rotatable relatively to the other, said members being provided with interleaved plates, and a support for the rotatable members comprising a hollow shaft provided at one side with transverse slits into which the plates of the rotatable member are extended and secured, said shaft being cutaway at the side opposite said slits to increase the distance between the shaft and the stator plates when the stator and rotor plates are in their unlapped position.

2. In an electrical condenser, the combination of a pair of members, one of which is rotatable relatively to the other, said members being provided with interleaved plates, and means for supporting the plates of one of-said members comprising a pair of transversely extending members provided with integral radially extending arms, and longitudinally extending bars to which the plates of said one member are fixed, the ends of said 3. In an electrical condenser, the combination of a pairof members, one of which is rotatable relatively to the other, said members being provided with interleaved plates, and means for supporting the plates of one of said members comprising a pair of members provided with transversely extending arms, longitudinally extending bars to which the plates of said one member are fixed, and transversely extending posts formed of insulating material and disposed between the bars and arms, said posts being connected to said arms to form continuations thereof.

4. In an electrical condenser, the combination of apair of members, one of which is rotatable relatively to the other, said members being provided with interleaved plates, and means for supporting the plates ofone of said members comprising supporting arms, longitudinally extending bars to which the plates ofsaid one member are fixed, in-

sulating posts forming continuations of the arms, and screws for securing the bars to said posts, the inner ends of the p a threaded to said arms.

v 5. In an electrical condenser the combination of a pair of members, one of which 1s movablerelatively totheother, each of said members being provided with interleaved plates, means for supporting the plates of the stationary one of said members, said means comprising supporting arms, longitudinally extending bars to which the plates are fixed, insulating posts forming continuation of the arms, and means'for securing said bars -to said posts.

6. In an electrical condenser, a shaft with a plurality of rotor plates secured thereon,

a plurality ofinterleaved stator plates with spacer bars secured thereon, a pair of frame members journaled on the rotor shaft and arms of insulating material secured between said frame members and the. ends of said spacer bars.

7. In an electrical condenserhaving stator and rotor plates, a central shaft carrying said rotor plates, spacing bars for said stator plates, a pair of spiders 'havingflthe rotor shaft journaled in the center thereof, tubes of insulating material carried by the spider arms and screws through the ends of the spacing bars and threaded in the free ends of I the insulating tubes to insulatingly secure the spider arms-to the'spacing bars,

8. In an electrical condenser having fixed Signed at Chicago, Illinois, this 3rd dayof November, 1924.

JAMES C. SNELL,

post bein 4 

